The Mackie SRM1801 18" Powered Subwoofer delivers powerful, chest-thumping lows, perfect for your SRM450v2 PA system. The SRM1801 has a ported bass reflex design that produces tight low end. And the lightweight, ultra-efficient Class-D Fast Recovery™ power amplifier delivers 1000W peak power with less risk of thermal overload. This makes the sub extremely lightweight and portable, without compromising the power and performance that you need. It's the first ever 18" subwoofer specifically designed for use with the best-selling SRM450v2—add some serious low end to your portable PA with the SRM1801.